1. Field of the Invention
The present invention relates to a method and a kit for positively detecting the presence of toxic materials within a sample and measuring the toxicity level thereof.
2. Description of the Related Art
Damage caused by an increase of hazardous materials due to industrialization such as environmental hormones, ecosystem damage caused by an increase of water pollution sources such as due to wastes and agricultural chemical components, damage caused by residual agricultural chemicals in food and heavy metal contamination in soil increasing on a daily basis, threaten human bodies and the environment.
Therefore, there is a need to monitor the harmfulness of chemical materials that may have negative influences on human bodies and the environment.
Various biological analysis methods for detecting toxic materials within environmental samples are known.
For example, U.S. Pat. No. 4,808,517 discloses an analysis method of toxic materials within an environmental sample including: mixing (a) a suspension of sub-mitochondrial particles having competent mitochondrial enzymes formed from inner membranes of mitochondria, (b) an analysis medium including a substrate in which either a substrate or an enzyme reaction product thereof may be detected using a spectroscopic detection method when the analysis medium is converted by mitochondrial enzymes, and (c) environmental samples in a common vessel, and determining how the sample influences enzyme activity within the suspension particles by measuring the changes of the substrate using spectroscopic measurement.
Such method can screen most toxic materials. However, since an instrument for spectroscopic measurement is required when applying that method, simplification of the method may not be possible. Also, the method cannot measure the toxicity levels of toxic materials. Also, such method is a negative detection method, which is different from a general positive detection mechanism, and thus, commercialization of the method is also not possible.
FIGS. 1A and 1B are graphs illustrating a concept for a method of negative detection and positive detection, respectively. Referring to FIG. 1A, negative detection measures the inhibition of a specific reaction caused by toxicity. Accordingly, small signal changes occur in the level of biological activity when toxicity exists due to the inhibition of the reaction. Conversely, significant signal changes occur in the level of biological activity when toxicity does not exist due to the absence of inhibition.
Referring to FIG. 1B, when a positive detection method is used, signal changes do not occur when toxicity does not exist and significant signal changes occur when toxicity does exist.
Some positive detection methods of detecting presence of toxic materials within a sample are known in the art. One example is a biosensor formed from a recombinant bioluminescent bacteria in which stress promoters and lux genes are transformed. Such biosensor generates a signal when specific toxic materials exist. (Sue-Hyung Choi and Man-Bock Gu, Phenolic Toxicity Detection and Classification Through the Use of a Recombinant Bioluminescent Escherichia, ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2001: Vol. 20, No. 2, pp. 248-255).
However, such biosensors are selective when detecting specific toxic materials and detect toxic materials that cause certain stress. Thus not all of the various kinds of toxic materials can be screened, and accordingly, not all toxicity levels can be measured.